What is the difference between translocation and addition?

The answer is

Recombination is an exchange between homologous chromosomes (e. g. chr 1 from mom x chr 1 from dad). Since it usually happens during meiosis, these strands are later separated. Recombination can be unequal or equal, but it's usually equal, and unequal crossovers are generally quite small (but a common source of addition/deletion).

Reciprocal translocation refers to an exchange between different chromosomes (e. g. chr 1 x chr 2). It is considered a large scale mutation (resulting in a large addition to one chromosome, and a large deletion in another).